1. Technical Field
The present invention relates to a crystal of 2-(3,4-dichlorobenzyl)-5-methyl-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidine-6-carboxylic acid (hereinafter to be referred to as “compound A”) useful as a therapeutic drug for dysuria and the like, a medicament containing the crystal and a production method of the crystal.
1. Background Art
Compound A is a compound described in WO 2006/135080 (see patent document 1), which has a high PDE9 inhibitory action as well as a mild PDE5 inhibitory action, and is useful for the treatment or procedure of dysuria and the like.
However, patent document 1 does not clearly show concrete properties of the obtained compound A and does not describe or suggest the presence of crystal polymorph.